The present invention relates generally to a radioactive source train for medical applications, and more particularly relates to an enclosed or jacketed radioactive source train that acts and moves as one unit as it travels through a catheter or tubular member with one or more lumens for the delivery of radiotherapy within the body of a patient.
Intraluminal radiation has been used after angioplasty or atherectomy to treat the affected area of the artery in order to inhibit cell proliferation and, consequently, helped prevent restenosis. Methods and apparatus for such intraluminal radiation treatment are disclosed in U.S. Pat. Nos. 5,899,882 and 6,013,020 and pending applications Ser. Nos. 09/304,752, filed May 4, 1999, Ser. No. 09/469,510, filed Dec. 22, 1999, and Ser. No. 09/522,759, filed Mar. 10, 2000, all of which are incorporated herein by reference. These applications generally disclose apparatus comprising a catheter which is inserted intraluminally into the patient and advanced to the site to be treated. A transfer device is provided for facilitating either the hydraulic or pneumatic advancement and retrieval of individual radioactive treating elements or xe2x80x9cseedsxe2x80x9d along the catheter to and from the treatment site.
As with any device inserted into the vascular system, it must have sufficient integrity to insure that no pieces or elements are separated from or exit the device into the vascular system. This is particularly true for the treating elements, which are moved to and from the distal end of the catheter. Additionally, because the treating elements are intended to be radioactive, there is a heightened need for safety. Specifically, there is a need to keep track of all of the radioactive treating elements to make sure that all are accounted for. The small size of the treating elements further complicates matters by making visual confirmation of the location of the treating elements more difficult.
Accordingly, it is a principle object of the present invention to provide a treating element source train that keeps the plurality of treating elements together so as to form a single unit.
It is an additional object to provide a source train that is flexible and allows for variable length.
It is a further object of the present invention to provide such a source train system that facilitates the visual confirmation of the location of the source train.
It is a still further object to provide such a source train system that does not interfere with the pattern of radioactive emissions from the treating elements.
These objects, as well as others which will become apparent upon reference to the following detailed description and drawings are accomplished by a treating element source train that comprises a plurality of treating elements, with each treating element comprising a hollow outer housing closed on each end and a radiation emitting substance encapsulated therein. The treating elements are aligned end-to-end, and one or more wires are wound around the exterior of the treating elements to maintain the treating elements in their end-to-end relationship. The wire may be helically coiled about the treating elements, or braided around them. Also, the wire may be secured to the proximal and distal treating elements, or to each individual treating element. If desired, the wire can be made of a radiopaque material such as gold, platinum, platinum iridium, tungsten, and tantalum.
In an alternate embodiment, the source train may be provided with an end cap at either end, with the wire jacket being secured to each endcap.